The present invention relates to apparatus, such as filmstrip/slide or animation stand equipment, for optically copying to a desired scale with good resolution small film images which includes enlarging the images and then copying the latter or variants thereof by a reproducing camera at a small ratio focusing distance or greater.
Such stand apparatuses are employed photographically to reproduce photograph images or artwork composed of desired variants of the latter or other optical compositions, and such artwork may, for example, have a width size range varying from about three to thirty-five inches (.+-.3 -35 inches). Usually these stands characteristically include camming mechanisms for adjusting automatically the focuses of the lenses of reproducing cameras mounted thereon with axes of their aligned lenses and gates arranged substantially vertically and directed downward to lateral supporting tabletops thereof, the camera mountings being such as to allow ready vertical adjustments including zooming. Focal lengths of normal and special lenses for such reproducing cameras usually vary from about 25 mm to about 150 mm, and very few such stands are provided with specially designed lenses for copying small image areas or automatic focus cams for the latter since sharp focus becomes highly critical in the area of 1:1 and the thickness of the material being copied varies enough to require manual adjustments on many exposures. Also, since a 1:1 lens is at a distance equal to its focal length it must be located very close to the copy material which interferes with the necessary handling of this material enough to require undesirable consumption of time. Consequently, for such productions practitioners in this art frequently resort to the use of separate costly special printers having special lenses and micrometer controls, while others attempt to do their small copy work by the use of special equipments of the following types that are objectionable for the reasons, among others, there indicated.
I. Enlarging technique includes the making of an enlargement from the small image of the film frame transparency and then copying the enlargement. This practice involves the problem of production of a final copy that lacks sharp definition since it was made from an intermediate copy and possibly with the use of further intervening copies with each such operation losing something as to the desired sharp definition.
II. Rear projection is employed by some to enlarge the small image of the film frame transparency in projecting this image upon the back of a light transmitting screen and copying this projected image from the front of this screen. This practice is objectionable since the beam of light carrying the image must be directed up from beneath the tabletop as the screen, which makes it difficult to use. Also, the reproducing camera receives a beam carrying the image which is desired to be reproduced and also images of all imperfections of the light transmitting screen, so that an even field of light is almost impossible to obtain thereby.
III. Aerial image printing apparatuses (which may be of the types described in the Oxberry U.S. Pat. Nos. 3,040,619 of June 26, 1962; and Oxberry et al. 3,682,540 of Aug. 8, 1972) may be employed to project through systems of lenses, condensers, and mirrors thereof images of the small film transparencies which are desired to be reproduced in the reproducing cameras. The only image that is observed by the camera is the resulting enlarged image and this may be considered to be a good system for resolution. However, a special lens is required for the camera and the latter must remain at a fixed position. Also, the camera cannot crop in on a section of the image and color correction is difficult. Further, this system is very costly and much more expensive than the costly special printers that are employed by some technicians in this art.
IV. Others have suggested the use of a front projection system for this purpose, but in such a system the projector is positioned adjacent to and alongside of the reproducing camera with the axis of the path of its projection beam being as parallel as is possible to the axis of the beam path extending back to the camera lens and gate. Such a system is used primarily in a horizontal position while advantageously filmstrip/slide and animation stand equipments operate in a vertical mode, and this "front projection" system is not only costly, but demands an unusually or undesirably large amount of space.
V. Magnifying systems have been tried in each of which a magnifying lens is placed over each small film frame image to enlarge it for reproduction thereof by the reproducing camera. Such efforts have been unsuccessful since the results obtainable do not measure up to the professional standard demanded.
A general object of the present invention is to provide an economically produced apparatus to be employed reliably with standardized equipment normally available in the art of optically copying to desired scale reproductions or intended and desired variants of small film images while attaining good resolution and excellent color reproduction or correction in the copies.
Another object of the invention is to provide such equipment which may be easily employed to advantage with filmstrip/slide or animation stand apparatuses that can be existing standard equipment in the operator's plant so as to require little additional investment and simple and rapid installation while requiring no great skill to set up for use.
An additional object of the invention is to provide in a simple manner and allow easy and reliable use for producing desired art work including altering, color correcting and accomplishing special optical effects in the otherwise usual copy producing procedure.
A further object of the invention is to provide such supplemental and relatively low cost and easily used equipment which allows either of a filmstrip/slide stand or an animation stand as an optical printer for the production of motion picture film.
Briefly, apparatus of the present invention includes in combination with an equivalent of a filmstrip/slide or animation stand apparatus, a reproducing camera mounted upon an upright track support for elevational adjustment and having the axis of its focally adjustable lens and its gate arranged substantially downward, and a lateral tabletop supported below the camera lens for interception of the axis of the latter thereby. Means define an internal chamber which has a lateral bottom wall and an entrance upright sidewall with a top portion of this means having a relatively large opening down through which the axis of the reproducing camera lens extends to the top face of the bottom wall and with the entrance wall having a beam entrance window. Means also provide the top face of the bottom wall with a screen surface upon which an image bearing beam may be projected to form an image of good quality for photographic transfer upwardly into the reproducing camera, and means support a projector with the optical axis of its gate and projecting lens arranged substantially laterally and extending through the beam entrance window into the chamber. An oblique transparent mirror is mounted in the chamber behind the entrance window and its canted forward toward the latter sufficiently so that its reflective surface receives image bearing beams from the projector and reflects them downward to and upon the top face screen for reflection back upward through the transparent mirror and the top opening for reception by the camera; this transparent mirror being of good optical glass or equivalent material and of a thickness (.ltoreq.) one-eighth of an inch, (i.e., approximately equal to or less than one-eighth of an inch). The reflective coating of this transparent mirror is of a character whereby the ratio of light rays transmission to light rays reflection thereby desirably may be in the range of about 60:40 to 40:60, and the inner surfaces of the walls of the chamber structure except the bottom screen surface are of a character whereby they are effectively absorptive of the transmitted rays.